Process of cracking petroleum



` UNi-TEOsrA-Tss -11i-ArsNT' LEON i. LOWE, or sAN FRANCISCO, AND vFammiauci: C. Burr, OF Los ANcELiis, CALI- ronNIA, AssIcNOasro iaY-rnonucrs MANUFACTURING cisco, oAitIrOiaNizzr,A A" CORPORATION or CALIFORNIA.

rnooiis's or ORAOKING. PETNOLEUM.

Specication of Letters fatent.

Appiioauon ma January 15,'11917. serial No; 142,590.

To all 'whom t may concern.'

Be it known'that we, LEON P. LOWE and FREDERICK C. RUrr, respectively a citizen of the United States and a subject of the Emperorof Germany, and residin at the city and county of San Francisco, tate of California, and the city and county of Los Angeles, State of California, have invented new and useful Improvements in Processes vofCracking Petroleum, of ,which the ollowing is a specification.

It has long been known that if petroleum .is heated to a certain temperature, about erative. y

l100 F. and is brought into contact with any one of certain catalyzing substances, as iron or nickel, it is cracked into free carbon, heavy oils, the condensible hydrocarbons, gasolene and aromatic oils, and ixedgases.

However, a difficulty has been experienced in thev practical application of this knowledge to the production of the aromatic oils and gasolene. The principal obstacle encountered has been the deposition -of the carbon on thelinner surfaces of the iron pipe or other chamber in which the oil is heated, which has not only rendered it increasingly diilicult to transmit external heat through the walls of said pipe or chamber to the interior, but has eventually clogged upA the o1l passages and rendered the apparatus inop- Itis the-Object of the present invention to vto provide a process of cracking petroleum -and fractions thereof, such as distillate,

which shall be free from the above difliculty and objections, and which, moreover, will be thoroughly practical and economical.

ln the accompanying drawing, the figure is a longitudinal vertical section of the api w series of horizontal rows 'of superposed iron checker bars 8 in said chambers 6, successive Vto preheat the oil to' be treated. B

lrows of the seriesv being laid cross-wise of each other to act as bales, in the same manner as the checker brick-work of gas generators. These bars are preferably of a mate- `rial having a catalytic effect, that is, in some manner not understood, assisting in cracking the petroleum, when sufiiciently heated, into free carbon, heavy oils, condensible hydrocarbons and fixed gases.

By means of fluid fuel burners 9 discharg` ing into the lower -portions of said'4 cracking fchambers, and supplied with air by conduits 10 controlled by gates 1l, said bars are heated to a 'suitable temperature, and the gpetroleum, either in the presence of a catalyz`er or not, is cracked, as above explained,

care being taken not to raise the tempera' COMPANY, or SAN FRAN- PatentedSept. 7, 1920.

ture so high as to completely gasify the conf stituents of the petroleum, as is done in the manufacture of gas from Oil. The hot products of combustion esca e by conduits l2 Ileading from the cracking chambers near the top, discharging into a lower portion of `the preheater 2, and assing out throu h said iues 3. It will tli us be seen that tie residuum of the heat used for heating the catalyzers and cracking chambers is utilized i' ProP- erly manipulating the valves 5, care is taken that the temperature of the oil in the preheater 2 does not rise to, or above, that at which the oil is cracked, in the presenceof the'catalyzer, for in such cases the carbon would be deposited on the exterior of the iues 3 or in the interior of the pipes 4.

l/Vhile the interior of one of the crackin chambers is thus being heated, oil whic has been heated in the preheater is being sprayed on to the top of the series of catalyzing bars in the other cracking chamber, which bars have already been raised above the cracking temperature. This cracking takes place as the lighter constituents of the oil in the form of vapor pass through the interstices between the checkerbars and are raised to the cracking temperature in the presence 'of the catalyzer. The cracking chambers are lined with refractory material 13, preferably of a catalyzing nature.

Some of the free carbon thus liberated is deposited on the catalyzing agent, but the rest passes with the gasolene, aromatic oils,

heavy oils and fined gases through pipes 14' outlet pipel 17, the' size of the opening into a washing vessel 16 from Whichleads an through which can be regulated by a valve 18 so as to vary the pressure in the washing vessel 16 and' in the cracking' chamber in Willich the oilis being cracked, the gate 11 of said cracking chamber being closed. The pipes 14 opensuiliciently near to the bottom of the'washing vessel 16 so that the gases and the vapors ofthe gasolene and aromatic V oils are compelled to pass beneath thelevel of the heavy oils contained in said Vessel, and are thereby Washed from the free articles of carbon retained thereby.v aid heavy oils flow off through an overflow pipe 19.

When the cracking chamber is undergoing the preheating step, an excess of air s admitted to said chamber, thereby burning up any carbon 'which may have been collected on the surface of the catalyzer, and utilizing the heat of combustion of the carbon to heat the interior of the cracking chamber, and also the preheater.

By this process and apparatus, the diiculties heretofore encountered when cracking the petroleum in pipes are avoided. Such pipes Were heated externally, and consequently the inner surface of the pipe Was the hottest portion of the interior. The carlbon abstracted from the petroleum Was deposited on the interior'surfaces of the pipe,

and was diiiicult to remove and tended to clog up the pipe. In the present construction the deposited carbon can easily be burnt Volf, and in any case the loose bars of catalyzing material can easily be removed and others substituted therefor.

From the above description the successive steps of the above process Will have been apprehended'. 4One of the cracking chambers., as, for instance, that on the left, is first heated by the combustion of fluid fuel admitted through the burner 9, the products of combustion passing out through the conduit 12 and iues 3. The heating is continued until the temperature of the catalyzing bars is raised to over 11000 F., if it be desired to produce principally aromatic hydrocarbons, and the gate on the left-hand .side and the rate of flow of the oil around the ues 3 are so regulated that the oil in the preheater is heated to a temperature of 500 to 600 F. If found necessary the Huid fuel burner may be shut off and the air supply continued to equalize the temperature in the cracking chamber by reducing that in its lower portion and raising that in its upper portion. The valve 11 on the left is now closed as Well as the burner valves 19 and 20 and those on the right are open and-the valve 5 on the left is open and that on the right is closed. The heated oil then flows through the pipe 14 on the left and into the sprayer, by which it is sprayed on the top of the catalyzer bars, so that,

that it reaches the bottom of the 'vertical series-of catalyzing bars, it is cracked into condensible hydrocarbons, fixed gases, carbon and heavy oils. Part of the carbon is deposited upon the catalyzing bars and on the walls of the chamber and the rest is carried forward into thevvashing chamber in which the heavy oils and carbon arel retained, the latter being Washed from the condensible hydrocarbons and fixed gases by tion.

In the meantime, the cracking chamber on the right is being heated in precisely the same manner as described in regard to the cracking chamber on the left. Thus the process, though intermittent for each cracking chamber, is continuous for the production of condensible hydrocarbons.

It, Will be observed that the liquid in the Washing vessel is too hot to condense the vapors of aromatic hydrocarbons and gasolene, and therebythe carbon is eliminated Without the necessity of employing the two steps of first heating and then cooling to get rid of the carbon. i

lt is evident that'the general steps of th eavy oils', the condensible hydrocar-- in general higherr for aromatic hydrocarbons than for gasolene, and the rate of supply being slower.

The process can be carried out with 'the pressure in the cracking chambers- 6 equal to the atmospheric pressure, but the yield at such pressure would be comparatively small. At a higher pressure the yield is greater and the .product more uniform.

For the sake ofbrevity the Word petroleum in the claims is vto be understood asincluding fractions thereof, such asordinary' distillate.

What is claimed is 1. The process of crackin petroleum, Which consists in passin pro ucts of combustion through a crac ing chamber and into contact With openwork material therein to raise the temperature of said material above that at which petroleum is cracked with a production of carbon and condensible hydrocarbons, but less than that to yvhich it is heated in the generation of gas from petroleum, then passing petroleum therethrough, thereby cracking .the petroleum,

then arresting the passage of the petroleum through the openwork material, and then burning the carbon deposited upon said surface by the crackin of the petroleum, to assist in heating sai surface in ay repetition of the process,

2. The process of cracking petroleum, Which consists in passing hot products of combustion alternately through two Cracking Chambers containing openwork material to heat the material in each of said chambers alternately to a temperature above that at which petroleum is cracked with a pro- 10 duction of carbon and condensible hydrocarbons, and less dthan that used to convert petroleum substantially completely into permanent gas and simultaneously passing petroleum through the other cracking cham l5 

